The invention claimed and disclosed herein pertains to cartridges for containing an imaging substance (such as ink or toner) used by imaging apparatus to generate an image, and to methods and apparatus for indicating the level of imaging substance with such a cartridge.
The present invention pertains to what is commonly known as xe2x80x9cprinter cartridgesxe2x80x9d or xe2x80x9cimaging cartridgesxe2x80x9d. These cartridges may better be termed xe2x80x9cimaging substance cartridgesxe2x80x9d since they are configured to contain an imaging substance, such as an ink or a toner. The imaging substance is used by an imaging apparatus (defined below) to produce an image on imaging media (such as paper or the like). In order to facilitate handling of the imaging substance by a user of the imaging apparatus, the imaging substance is commonly provided within a container (a xe2x80x9ccartridgexe2x80x9d) that is configured to be installed in, and removed from, the imaging apparatus. The cartridge is typically designed to prevent leakage of the imaging substance from the cartridge when the cartridge is handled by a user or installed in the device, but is also designed to allow the imaging apparatus to selectively remove the imaging substance from the cartridge during an imaging process.
By xe2x80x9cimaging apparatusxe2x80x9d we mean any apparatus configured to use an imaging substance to generate an image on sheet media, such as on paper or a transparency. Examples of imaging apparatus include (without limitation) printers, photocopies, facsimile machines, plotters, and combinations thereof (i.e., imaging apparatus commonly known as xe2x80x9call-in-onexe2x80x9d imaging apparatus or xe2x80x9cmultifunction peripheralsxe2x80x9d). Example of imaging processes that can be used by imaging apparatus include electrophotographic imaging, including laser printing, and ink printing, including ink jet printing. Two primary types of imaging substance are provided to imaging apparatus via a cartridge. These primary types of imaging substance include wet ink and dry toner. Dry toner (xe2x80x9ctonerxe2x80x9d) is commonly provided as powdered carbon black or very small particles of plastic (as in the case of non-black toners).
When the imaging substance within a cartridge becomes depleted, the user typically replaces the spent cartridge with a replacement cartridge that contains additional imaging substance. The user may not always have a replacement cartridge on hand, or the replacement cartridge may not be easily accessible. Accordingly, a user may be put in the position of not being able to complete an imaging job due to a lack of imaging substance. It is therefore desirable that a user should be able to periodically check the level of remaining imaging substance within an imaging cartridge to thereby have some advance notice of impending depletion of the imaging substance from the cartridge.
A number of different prior art methods and apparatus exist for detecting or estimating the remaining quantity of imaging substance within an imaging cartridge. One such prior art method, described for example in U.S. Pat. No. 5,724,627, uses a xe2x80x9cpixel counterxe2x80x9d. The pixel counter essentially comprises an algorithm which is executed by a processor in the imaging apparatus and which calculates (estimates) the usage of imaging substance based on the number of pixels imaged by the imaging apparatus since the time the current imaging cartridge was installed. However, such pixel counters are not always accurate, with obvious undesirable consequences (specifically, the imaging substance in the cartridge becomes exhausted before the pixel counter indicates it should be exhausted). Another prior art method for allowing a user to determine the remaining imaging substance within an imaging cartridge is to place a transparent or translucent viewing window in the cartridge, such as described in U.S. Pat. No. 5,890,049. However, the imaging substance can coat the inside of the viewing window, making it difficult or impossible to see into the cartridge and thus determine the quantity of imaging substance remaining in the cartridge.
Other prior art level detection devices include sensors placed within the cartridge. One example of this type of level detecting system is described in U.S. Pat. No. 5,587,770, wherein a light-emitting element and a light-receiving element are placed within a toner cartridge. When toner is absent between the two elements (resulting from a low level of toner), the light-receiving element will be able to receive light from the light-emitting element, indicating low toner level. Another sensor-based device is described in U.S. Pat. No. 5,583,545, wherein an electrical device is used in combination with a back-pressure regulator apparatus to sense a back-pressure in the cartridge after the imaging substance has been depleted. The problem with both of these systems is that they typically only alert a user when the cartridge is depleted of imaging substance (or very near depletion). Further, these types of level detection systems add a relatively complex system to what is essentially a consumable component (the cartridge).
What is needed then is a simple, effective way to allow a user to determine the approximate remaining quantity of imaging substance within an imaging cartridge.
In one embodiment the present invention provides for includes an imaging substance cartridge which includes a cartridge body that defines an imaging substance chamber. The imaging substance chamber can contain an imaging substance, as for example toner or liquid ink. The cartridge includes an imaging substance level indication device. The imaging substance level indication device includes a level indication actuator supported in the cartridge body, and which is configured to displace a vapor volume within the imaging substance chamber. The imaging substance level indication device further includes an imaging substance level indicator supported by the cartridge body. The imaging substance level indicator is responsive to the displacement of vapor volume within the imaging substance chamber.
These and other aspects and embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein: